A selection experiment with pigs: comparison of the effectiveness of individual selection and sib selection.

Abstract

One young boar and 4 full sibs (2 barrows and 2 gilts) were chosen from each of 40 herdbook litters of the Dutch Landraoe breed and fattened from 22 to 90 kg. live weight. Backfat thickness and the area of the cross-section of the longissimus dorsi muscle were measured on the live boars by means of ultrasonics. The full sibs were slaughtered, and measurements were made of backfat thickness and the percentage of cutlets in the carcasses. Eight of the boars, representing some of the best and some of the poorest, as judged by their own performance or the av. performance of their full sibs, were eventually chosen for breeding on the basis of a selection index which took into consideration food conversion, daily gain, backfat thickness, and either the area of the 1. dorsi muscle (live boars) or the percentage of cutlets (hi carcasses). 20-23 [female] progeny from each boar were taken from the same number of litters and fattened from 22 to 90 kg. live weight. Food conversion, daily gain, area of 1. dorsi muscle and percentage of cutlets were determined. The last 3 characters were measured on the carcasses. Both selection methods were found to be effective, but the response was non-significantly (1-9 times) greater with individual selection than with sib selection. Theoretical considerations also showed that individual selection is superior to sib selection. An additional advantage of individual selection is that it requires fewer pens. (Abstract retrieved from CAB Abstracts by CABI’s permission)